As Mohammed Rajoub watched a Jordanian military helicopter climb slowly into the air early Friday with the ailing Palestinian leader Yasser Arafat aboard, he turned to hug his friends and cried.

"I can't believe my eyes," said Rajoub, 20, wearing a black-and-white checkered head scarf like the one Arafat typically wears, tears streaming down his face. "He left us. Who is going to take care of us? Who is going to listen to us?"

"There's nobody like him, and nobody will replace him," said glassy-eyed Iyad Murar, 41, who had waited for six hours outside Arafat's dilapidated compound to watch his 7:20 a.m. departure. "He will never come back."

That sentiment was shared by many Palestinians here and across the region as the 75-year-old man considered the embodiment of his people's fight for an independent homeland left his barricaded headquarters for the first time in more than two years to seek medical treatment in Paris.

Some analysts said his departure would renew hope for reviving the peace process with the Israelis and reforming the Palestinians' political and security institutions. But others said a power vacuum could leave the peace process stalled and lead to clashes between Palestinian armed groups and political factions.

"If Arafat dies or is incapacitated, we're looking at what I would call a revolutionary situation, in the sense that all kinds of dynamics will be released," said Yossi Alpher, co-founder of Bitterlemons.org, a Web site for Palestinian-Israeli dialogue.

Arafat's departure for France forced Palestinians to contemplate life without the one person who not only embodies their diverse interests -- he is a Nobel Peace laureate, president of the Palestinian Authority, chairman of the Palestine Liberation Organization and chief of the Fatah political movement -- but for decades has kept them from flying apart.

Arafat's charisma, popularity and international profile have given him power and influence on both sides of some of the Palestinians' deepest divides: with the 3.6 million Palestinians who live in the West Bank and Gaza Strip and the 2.5 million Palestinian refugees in Jordan, Syria and Lebanon; among the old guard cronies who joined him in exile in Jordan, Lebanon and Tunisia, and the younger reformers who grew up in the territories; with the Islamic groups that want to turn the fight against Israel into a holy war, and the secular organizations that want to keep it a struggle of national liberation.

"The importance of Arafat is not in his title as president," said Henry Siegman, a Middle East analyst at the Council on Foreign Relations in New York. "His importance is derived by his image as the incarnation of the national identity and struggle. Once he's gone, there's no one to replace him. No one can claim to inherit that mantle."

But at the same time, Arafat has made enemies not only abroad but at home over his style and tactics, the corruption that has festered around him, his spurning of democratic reforms and the lack of progress in the Palestinian drive for statehood. Supporters of the peace process, in particular, have been angered by Arafat's refusal to prevent suicide bombers of the al-Aqsa Martyrs Brigades, a military wing of his Fatah movement, from killing Israeli civilians.

The Islamic Resistance Movement, or Hamas, a chief rival of Fatah and the Palestinian Authority, said Friday that it was setting aside its differences with Arafat and called for a united Palestinian leadership to work toward elections. In an interview on al-Jazeera television, Ismail Haniyeh, a leader of Hamas in the Gaza Strip, wished Arafat well and added, "We wish that the siege against the entire Palestinian people and President Arafat was broken."

Arafat has refused to groom an heir and has not permitted a new generation of leaders to flourish under his command. As a result, several of the most popular Palestinians have developed their own followings in different factions and geographic areas, creating the potential for bitter power struggles, analysts say.

Hillel Frisch, a political scientist at the Begin-Sadat Center for Strategic Studies outside Tel Aviv, predicted "a tremendous crisis in the Palestinian political center," with several politicians and security officials amassing support and influence. These include Mohammed Dahlan, the former security chief of Gaza; Brig. Gen. Jibril Rajoub, Arafat's national security adviser; and Marwan Barghouti, a West Bank leader jailed by Israel on terrorism charges.

"They feel it's their time for the job, and they're not going to allow the oldies to run the show," Frisch said.

But among potential replacements, "everybody, whether they're Arafat cronies or rivals, belongs to the same elite," said Mouin Rabbani, a Middle East analyst for the International Crisis Group in Amman, the Jordanian capital. "And the question is, can they survive his absence, and can they hold the Palestinian national movement together?"

When Arafat returned from 27 years in exile in 1994, "everybody went outside and greeted him, and I was one of them," said Abu Hussein, 51, a Ramallah businessman who refused to give his full name for fear of retribution. "But those guys came from the outside in order to steal our money and to steal our dream and to steal our future. I wish all of them would leave."

"Anybody who succeeds Arafat will be better than him," said Abdul Jawad Saleh, an independent member of the Palestinian parliament and a critic of Arafat's one-man rule.

Among the Palestinian public, Barghouti, 45, is the most popular. But the firebrand politician, who as Fatah's West Bank leader was considered a founding father of the four-year-old Palestinian uprising, is serving five consecutive life sentences for attempted murder and membership in a terrorist organization.

Within the Palestinians' political institutions, Prime Minister Ahmed Qureia and his predecessor, Mahmoud Abbas, who resigned a year ago in a power struggle with Arafat, are expected to play major roles after Arafat dies or steps aside. Both have temporarily assumed some of Arafat's duties while he is away.

Israel and the United States have refused to deal with Arafat, accusing him of fomenting terrorism. Sharon complains that there is no partner for peace on the Palestinian side, which has forced him to act unilaterally -- building a wall through and around the West Bank and proposing a withdrawal of settlers and soldiers from the Gaza Strip.

But Arafat's departure would not necessarily mean that a partner will emerge, said Frisch, the professor.

"Sharon's going to say, 'I'm waiting for my partner, and there's only one provision -- dismantle terrorist organizations -- so let the Palestinian leader arise who can do it,' " Frisch said. "And he can speak with that rhetoric for a long time, because no Palestinian can deliver that."

But other analysts that said Arafat was the perfect foil for Sharon, providing him with an excuse to do whatever he wanted and that his absence would force Sharon back to the bargaining table.

"If Sharon has a strategic goal and clear vision, it is the need to avoid at all cost a political process, and the most important pretext for doing so is Arafat," said Siegman, of the Council on Foreign Relations. "Once he disappears, there's going to be great pressure to say, 'Get back to the process, you no longer have that excuse.' "

Moore reported from Jerusalem. Special correspondent Sufian Taha contributed to this report.

Palestinians wave at the helicopter carrying Yasser Arafat as he leaves his compound in the West Bank city of Ramallah to seek medical care in Paris.Arafat waves to a crowd before leaving his barricaded compound. Many consider him the embodiment of the Palestinian fight for a homeland.